Timing of Transfer and Mortality in Neonates with Hypoplastic Left Heart Syndrome in California.

Maternal race/ethnicity is associated with mortality in neonates with hypoplastic left heart syndrome (HLHS). We investigated whether maternal race/ethnicity and other sociodemographic factors affect timing of transfer after birth and whether timing of transfer impacts mortality in infants with HLHS. We linked two statewide databases, the California Perinatal Quality Care Collaborative and records from the Office of Statewide Health Planning and Development, to identify cases of HLHS born between 1/1/06 and 12/31/11. Cases were divided into three groups: birth at destination hospital, transfer on day of life 0-1 ("early transfer"), or transfer on day of life ≥ 2 ("late transfer"). We used log-binomial regression models to estimate relative risks (RR) for timing of transfer and Cox proportional hazard models to estimate hazard ratios (HR) for mortality. We excluded infants who died within 60 days of life without intervention from the main analyses of timing of transfer, since intervention may not have been planned in these infants. Of 556 cases, 107 died without intervention (19%) and another 52 (9%) died within 28 days. Of the 449 included in analyses of timing of transfer, 28% were born at the destination hospital, 49% were transferred early, and 23% were transferred late. Late transfer was more likely for infants of low birthweight (RR 1.74) and infants born to US-born Hispanic (RR 1.69) and black (RR 2.45) mothers. Low birthweight (HR 1.50), low 5-min Apgar score (HR 4.69), and the presence of other major congenital anomalies (HR 3.41), but not timing of transfer, predicted neonatal mortality. Late transfer was more likely in neonates born to US-born Hispanic and black mothers but was not associated with higher mortality.

MCTP2 is a dosage-sensitive gene required for cardiac outflow tract development.

Coarctation of the aorta (CoA) and hypoplastic left heart syndrome (HLHS) have been reported in rare individuals with large terminal deletions of chromosome 15q26. However, no single gene important for left ventricular outflow tract (LVOT) development has been identified in this region. Using array-comparative genomic hybridization, we identified two half-siblings with CoA with a 2.2 Mb deletion on 15q26.2, inherited from their mother, who was mosaic for this deletion. This interval contains an evolutionary conserved, protein-coding gene, MCTP2 (multiple C2-domains with two transmembrane regions 2). Using gene-specific array screening in 146 individuals with non-syndromic LVOT obstructive defects, another individual with HLHS and CoA was found to have a de novo 41 kb intragenic duplication within MCTP2, predicted to result in premature truncation, p.F697X. Alteration of Mctp2 gene expression in Xenopus laevis embryos by morpholino knockdown and mRNA overexpression resulted in the failure of proper OT development, confirming the functional importance of this dosage-sensitive gene for cardiogenesis. Our results identify MCTP2 as a novel genetic cause of CoA and related cardiac malformations.

Effects of race, ethnicity, and gender on surgical mortality in hypoplastic left heart syndrome.

Information is limited regarding the effect of race, ethnicity, and gender on the outcomes of the three palliative procedures for hypoplastic left heart syndrome (HLHS). This study examined the effects of race, ethnicity, gender, type of admission, and surgical volume on in-hospital mortality associated with palliative procedures for HLHS between 1998 and 2007 using data from the University HealthSystem Consortium. According to the data, 1,949 patients underwent stage 1 palliation (S1P) with a mortality rate of 29 %, 1,279 patients underwent stage 2 palliations (S2P) with a mortality rate of 5.4 %, and 1,084 patients underwent stage 3 palliation (S3P) with a mortality rate of 4.1 %. The risk factors for increased mortality with S1P were black and "other" race, smaller surgical volume, and early surgical era. The only risk factors for increased mortality with S2P were black race (11 % mortality; odds ratio [OR], 3.19; 95 % confidence interval [CI] 1.69-6.02) and Hispanic ethnicity (11 % mortality; OR 3.30; 95 % CI 1.64-6.64). For S2P, no racial differences were seen in the top five surgical volume institutions, but racial differences were seen in the non-top-five surgical volume institutions. Mortality with S1P was significantly higher for patients discharged after birth (37 vs 24 %; p = 0.004), and blacks were more likely to be discharged after birth (12 vs 5 % for all other races; p < 0.001). No racial differences with S3P were observed. The risk factors for increased mortality at S1P were black and "other" race, smaller surgical volume, and early surgical era. The risk factors for increased in-hospital mortality with S2P were black race and Hispanic ethnicity.

Socioeconomic Status and Long-term Outcomes in Single Ventricle Heart Disease.

BACKGROUND: Low socioeconomic status (SES) has emerged as an important risk factor for higher short-term mortality and neurodevelopmental outcomes in children with hypoplastic left heart syndrome and related anomalies; yet little is known about how SES affects these outcomes over the long-term. METHODS: We linked data from the Single Ventricle Reconstruction trial to US Census Bureau data to analyze the relationship of neighborhood SES tertiles with mortality and transplantation, neurodevelopment, quality of life, and functional status at 5 and 6 years post-Norwood procedure (N = 525). Cox proportional hazards regression and linear regression were used to assess the association of SES with mortality and neurodevelopmental outcomes, respectively. RESULTS: Patients in the lowest SES tertile were more likely to be racial minorities, older at stage 2 and Fontan procedures, and to have more complications and fewer cardiac catheterizations over follow-up (all P < .05) compared with patients in higher SES tertiles. Unadjusted mortality was highest for patients in the lowest SES tertile and lowest in the highest tertile (41% vs 29%, respectively; log-rank P = .027). Adjustment for patient birth and Norwood factors attenuated these differences slightly (P = .055). Patients in the lowest SES tertile reported lower functional status and lower fine motor, problem-solving, adaptive behavior, and communication skills at 6 years (all P < .05). These differences persisted after adjustment for baseline and post-Norwood factors. Quality of life did not differ by SES. CONCLUSIONS: Among patients with hypoplastic left heart syndrome, those with low SES have worse neurodevelopmental and functional status outcomes at 6 years. These differences were not explained by other patient or clinical characteristics.

Congenital left heart obstruction: ethnic variation in incidence and infant survival.

OBJECTIVE: To investigate the relationship between ethnicity and health outcomes among fetuses and infants with congenital left heart obstruction (LHO). DESIGN: A retrospective population-based review was conducted of fetuses and infants with LHO including all terminations, stillbirths and live births from 20 weeks' gestation in New Zealand over a 9-year period. Disease incidence and mortality were analysed by ethnicity and by disease type: hypoplastic left heart syndrome (HLHS), aortic arch obstruction (AAO), and aortic valve and supravalvular anomalies (AVSA). RESULTS: Critical LHO was diagnosed in 243 fetuses and newborns. There were 125 with HLHS, 112 with AAO and 6 with isolated AVSA. The incidence of LHO was significantly higher among Europeans (0.59 per 1000) compared with Maori (0.31 per 1000; p<0.001) and Pacific peoples (0.27 per 1000; p=0.002). Terminations were uncommon among Maori and Pacific peoples. Total case fatality was, however, lower in Europeans compared with other ethnicities (42% vs 63%; p=0.002) due to a higher surgical intervention rate and better infant survival. The perinatal and infant mortality rate was 82% for HLHS, 15% for AAO and 2% for AVSA. CONCLUSION: HLHS carries a high perinatal and infant mortality risk. There are ethnic differences in the incidence of and mortality from congenital LHO with differences in mortality rate suggesting inequities may exist in the perinatal management pathway.

Epidemiology of noncomplex left ventricular outflow tract obstruction malformations (aortic valve stenosis, coarctation of the aorta, hypoplastic left heart syndrome) in Texas, 1999-2001.

BACKGROUND: The left ventricular outflow tract (LVOT) malformations aortic valve stenosis (AVS), coarctation of the aorta (CoA), and hypoplastic left heart syndrome (HLHS) contribute significantly to infant mortality due to birth defects. Previous epidemiology data showed rate differences between male and female and white and black ethnic groups. The Texas Birth Defects Registry, an active surveillance program, enables study in a large, diverse population including Hispanics. METHODS: Records of children up to 1 year old with AVS, CoA, and HLHS born in Texas from 1999 to 2001, were collected from the registry. Those including additional heart defects or a chromosomal anomaly were excluded. Multivariate analysis included: infant sex; United States-Mexico border county residence; and maternal age, race/ethnicity, birthplace, and education. RESULTS: There were 910 cases among 1.08 million live births, of which 499 met inclusion criteria. Multivariate modeling of all LVOT malformations combined demonstrated lower prevalence rate ratios (PRRs) for black males (0.26) and Hispanic males (0.70). Similar results were found for CoA but not AVS or HLHS. Higher PRRs were noted for increased maternal age for LVOT (1.3 for 24-34 years; 1.7 for >34 years), AVS, and HLHS, but not CoA, and higher PRRs across all diagnoses for males (LVOT PRR, 2.4) were noted. CoA PRRs were higher in border county vs. non-border county residents (PRR, 2.1). Maternal education and birthplace were not significant factors. CONCLUSIONS: There are rate differences for males among all 3 ethnic groups. Sex and ethnic differences suggest genetic etiologies, where the ethnic differences could be used to find susceptibility loci with mapping by admixture linkage disequilibrium. Increased CoA rates along the U.S.-Mexico border suggest environmental causes that will require further monitoring.